The Parker Single trigger mechanism’s selector would not allow for it to be operated like that up on the safety.
This gun has certainly been converted after the fact to a different style of trigger all together. Like I said, one of a more modern design. That style of selector is very common today on many O/U shotguns.

The gun appears to have original wood finish and barrel blue. It's an older recolor in factory style. These are the photos I had handy of the trigger and I can get more if needed. Thank you for your assistance.

There appears to be some kind of alpha-numeric stamp on the right side of the trigger... unless my iphone is playing tricks on my old eyes.





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I have a parker d grade hammerless with a odd ball trigger selector..it is on the left side of the left sideof the opening lever..on the left cheek panel of the stock..it pushes back and forth like the safety to choose the barrel you want to fire...to deep in the tomb to take a picture right now...my barrel selector looks nothing like this one being shown...but I have never seen another one like it...I like this selector being shown...you could choose whitch barrel to shoot in a hurry..you canchange barrels on mine in a blink of the eye..i have 2 lc smith with the hunter one barrel selectors a bird would be out of range real quick using those selectors...charlie

Dean,
That looks like the serial number on the trigger you are seeing peeking out from the slot.

This gun was a Double trigger gun originally.

Charlie,

That sounds like an infallible trigger in the gun you have. The selector on those was up on the left side of the tang.

Charlie, your trigger sounds like Alfred Harvey Worrest's Infallible Single Trigger as produced by his Lancaster Arms Co. Briefly in the teens Ithaca Gun Co. offered the Infallible Single Trigger on their Flues doubles.

Parker Bros. may have also used it a bit, as I have seen a 1913-vintage Parker Bros. Walter King letter to a customer where he says "As to your request we have removed our infallible single trigger, and installed the double trigger system."

I just looked it up by the pictures it is for sure infallible trigger system...charlie

Good work guys, I continue to be amazed!